1. Field of the Present Invention
The present invention relates generally to a container security system. More particularly, the present invention relates to a method for polling the contents of a cargo container while in transit and comparing an estimated payload weight derived from REID information with a measured payload weight to detect the presence of unidentified materials in a shipment and to produce a risk profile.
2. Description of Related Art
Many states have weigh-in-motion technology that allows a continuous flow of truck weighing. Many states now use electronic bypass systems to alleviate some of the truck traffic through the weigh station called simply A.V.I. (Automatic Vehicle Identification). The system consists of the equipment at the weigh station itself, as well as a truck mounted transponder, usually placed on the inside of the windshield. These are similar to transponders used for toll collection. Each transponder is directly registered to a specific truck, and contains a unique identification. The registration process propagates information such as carrier name, unit number, and gross weight to weigh stations. In addition, the system keeps a basic safety and compliance record for each vehicle. As a truck approaches a weigh station (approximately one mile before), an electronic “reader” on a boom over the freeway reads the information from the truck transponder. At the same time, the truck is usually driving over high-speed electronic scales embedded in the road.
The system computes the weight, by axle and gross, and determines if it is within the limits. It also looks at the safety and compliance record on the database. The display shows the results to the weigh master, including the speed of the vehicle. The weigh master may have the system automatically determine if a truck needs to stop or may override the system. Approximately one-half to one full mile after passing under the “reader,” the truck will pass under another boom which has an electronic unit to send the transponder a signal. If the weight and safety information are acceptable, the truck may receive a “green light” and can continue without entering the weigh station at all. When a driver receives a “red light,” the truck must pull into the weigh station for the normal weigh-in procedure. The most common reason a truck is “red-lighted” is a weight problem, or a random check. Each time a truck is randomly pulled in, it is noted in the system whether the driver was compliant or not during the check. This affects how often a truck or different trucks from the same company are pulled in. For example, a company with a good compliance record may have 5% of its trucks “red-lighted.” On the other hand, a company whose trucks have compliance issues during the random checks will have their information updated accordingly, and might get “red-lighted,” for example, 30% of the time.
However, there remains a significant security risk not addressed by the present method used to regulate freight carrier compliance. The present weigh station system and Automatic Vehicle Identification programs lacks a method to identify at risk containers especially as trucks enter the U.S. through ports of entry.